Halomethyl derivatives of dyes of the thioindigo series and process of obtaining them



Patented Mar. 20, 1951 HALOMETHYL DERIVATIVES OF DYES OF THE THIOINDIGO SERIES AND PROCESS I OF OBTAINING THEM Carl M. Smith and David I. Randall, Easton, Pa.,

assignors to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware No Drawing.

1 This invention relates to the production of halogen methyl derivatives of thioindigos.

Application December 28, 1949, Serial No. 135,518

6 Claims. (Cl. 260332) which have been found suitable for such conversion are those having the formulae:

Thioindigos have long been known as valuable (1) vat dyes. They are insoluble in aqueous and spirit solutions and cannot, therefore, be applied sub- 5 stantively to fabrics. They derive their dyeing properties from their capacity of passing into solution as leuco compounds when reduced and with alkaline agents. This treatment with reducing agents converts the insoluble dye to a (2) I 0 phenolic form by reduction of one or more of A A the keto groups. Applied to thioindigo, for example, the conversion is as follows: C C

/O O\ i i Alk. Rd. S S S wherein R is a fused 6-membered ring system; OH 26 n and n are the same or different integers from 0 to 2; X and Y are the same or difierent members of the roup consisting of H, alkyl, and halo.- gen; and n" is an integer from 1 to 2.

4 The chlormethyl derivatives are produced by Alkaline solutions of the reduced compounds 5 dissolving the thioindigo compound in a solvent possess a considerable affinity for cotton fibre and for the reactants, specifically 96% sulfuric acid, have the property of being readily reoxidized on introducing dichlordimethylether at room temtreatment by air with the precipitation of the perature and stirring the reaction mixture at original dyestufi. temperatures of from 30 to 80 C. for several Although this method produces a fast bond be- 30 hours. The activity of the chlormethylation retween the dye and the fibre due to the thorough action and, hence, the reaction time and the enimpregnation of the fibre with the leuco or tering position or positions of the chlormethyl reduced form of the dye and precipitation of the groups depends somewhat upon the blocking and dye on the fibre during oxidation, it is obviously directing influence of substituent groups. Thus, subject to limitations. Fabrics which are affectin the case of unsubstituted thioindigo the ed by alkali cannot be dyed by this method. Thus chlormethylation will be symmetrical with two in wool dyeing it would be necessary to neutralize entering chlormethyl groups as follows: the leuco or reduction solution. Some methods 0 O for ellecting that result have been proposed but H V have not been successfully employed. A more QH2G1 O GHZCI successful approach has been the use of leucoesters of the thioindigo dyes. Other problems S S are also inherent in the process of dyeing from l'euco vats. Carefully controlled coditions and CH G1 OH 01 special equipment are necessary. Boosters, such z 2 as glycols, must be added to maintai proper alkalinity. It is, therefore, an object of this invention to produce thioindigos in a form which can be used directly as a dye or a dye intermediate. The same symmetrical di-substitution takes It is a further object of this invention to proplace upon chlormethylating a symmetrically duce thioindigos which do not require alkaline substituted dial'kyl-dihalo thioindigo where the 5 solutions for dyeing. position is unsubstituted. When the 5 position is With these and other objects in mind, it has blocked as in symmetrical tetra-alkyl thioindigo, now been discovered that thioindigo and some the entering positions for chlormethylation'are of its derivatives may be converted to valuable dyes and dye intermediates by producing the halomethyl, particularly the chlormethyl derivative of the thioindigo compound. Thioindigos the symmetrical 7,7 positions. Where the thioindigo is unsymmetrical, containing a different number of fused hydrocarbon ring systems on either side of the C=C bridge, the substitution will follow the pattern of the following reaction:

CHzOl-O-CHaOl s s l 1 (I'IHzCI In unsymmetrically ring substituted types only one chlormethyl group may be introduced as in the following reaction:

CH: CH3

I oo 01 CHaCl-O- CHzCl and provided the 5 position is not blocked. When more than one fused benzenoid ring is present,

CICHrchlormethylation will take place more readily than in the case of mono benzenoid ring compounds, as for example thioindigo itself.

Some of the chlormethylated thioindigos produced in accordance with this invention may be vatted and used as dyes. However, all may be used as intermediates and by far their greatest utility may be realized by further condensation with amines and mercaptans to produce spirit and water-soluble dyes.

The invention will be further described with respect to the following examples, which are intended to illustrate it but not limit its scope. Unless otherwise stated, the parts are by weight.

Example 1 Chloromethylation of the thioindigo dye having the formula:

CH3 CH3 In a 2-liter, 3-necked flask fitted with thermometer, agitator, and drying tube was charged 750 cc. 96% sulfuric acid and 40 g. of the thioindigo dye of the above formula. When the dyestuff was evenly dispersed in the sulfuric acid, 25 cc. dichlorodimethyl ether was charged and the mixture stirred at room temperature (25-30 C.) (18 hours). 1101 was slowly evolved. The mixture was then heated to 40 C. HCl was Vigorously evolved. Held 1 hour at 40 C. and drowned worked up as in Example 1.

in ice. The mixture was filtered and the precipitate was washed neutral to litmus with cold water.

The product was obtained in a yield of 45.5 g. calculated as dry or 91.5% of theoretical. It has the formula:

CH; C H3 0 0 010E2- CHzCl Example 2 Chloromethylation of the thioindigo dye having the formula:

In a 2-liter, 3-necked flask fitted with thermometer, agitator, and drying tube was charged 750 cc. 96% sulfuric acid and 35.5 g. of the thioindigo dye of the above formula. When the dyestuff was thoroughly dispersed in the acid, 25 cc. dichlorodimethyl ether was added dropwise and the mixture stirred 18 hr. at room temperature (25-30 0.). The reaction mix was poured into ice, filtered, washed neutral to litmus with cold water and dried.

The product was obtained in a yield of 45.0 g. It has the formula:

HzCl CHaCl Example 3 Chloromethylation of thioindigo:

A solution of 14.8 g. thioindigo in cc. 96% sulfuric acid was prepared at 25 C. To the solution was added at 12.9 cc. bischloromethyl ether. The temperature was raised to 60 C. and held for 8 hours. After working up as in Example 1, 21.0 g. of a red dichloromethyl thioindigo were obtained containing 2-chloromethyl groups per molecule. The product has the formula:

CHnCl This product did not give a soluble vat and therefore cannot be used as a vat dye. It easily reacted with various amines and thioureas to yield useful colored compounds.

Ewample 4 Chloromethylation of the thioindigo dye having the formula:

s s CH3 A solution of the thioindigo shown above was dissolved in 200 cc. 96% sulfuric acid and to it was added 20 cc. bischloromethyl ether. For 16 hrs. the temperature was held at 25 C. and then The yield amounted as 21.5 grams and en ined 14.5%- efiie rine (thefiry for 2 chlorines 15.6%). Violet dyeifigs er good fastness properties were obtained which were noticeably bluer than those given by the starting material. w

In this case the 5,5" position or positions para to the S atom were blocked, as were also the meta positions. Acordingly the clilormethyl groups enter the 7,7 position ortho to the S atom. providing a product of the following formula:

0 OH CH;

CH \S S CH3 izier i'si Example 5 Chloroinethylation 6f the thioin'digo having the formula:

This dyestufij chloromethylates with somewhat greater difficulty than the dimthyldichlorothiourea of Example 1: By using the same ex-' perimental procedure and weights as in Example 1 and a temperature of 65-70 C. rather than 60 0., one 'chloromethyl group may be introduced. The new dye is considerably bluer than the original dyestufi. The yield is quantitative. It has the formula:

CH3 CH3 0 CICH 01 1 C s s Example 6 By following the same procedure and using the same quantities as in Example 1, the following chlormethylation may be efiected:

CHzCl The yield is quantitative and the chlormethylated dye product is somewhat bluer than the starting material.

Example 7 Chlormethylation of the thioindigo having the formula:

A solution of 10.0 g. of the thioindigo of the above formula was prepared in 90 cc. of 96% sulfuric Pef Gent Perfint ..Total Halogen Halogen Round na1.: I

For (unreacted) startingpr'oduct; 16.0

For 1 'CHzGl group introduced 21. 7 22. 7

For 2 CH;G1 groups introduced 27. 5

0 acid at 25 0'. To thissolution '10 cc. erasable-ro methyl ether was added. The resulting solution was Heated to 60 65- C: for 15 hours. The chlormethylated product which contains two chlormethyl groups was worked up in the same manher as the product of Example 1.

' Example 8' Chlormethylation of the thioindigo identified as: 9 chloro 2 [5 bromo-3-oxo-2(3)indolylidenelnaphtho'lI,2 b1thiophen=3=one. P

In a S-iiecked, 500 ask fitted with thermc'imeter, agitator, and directing tube, was charged 400 cc. 96% sulfuric acid, 22 g. of the thioindigo of the above formula purified, and 13 cc. '"clichlorodimthyl ether. The mixture was stirred 34 hours at room temperature, drowned on ice, filtered, washed neutral, and dried. Yield On vatting this product, dark blue color was completely destroyed. It produced a watemciuble product with trimethylthiourea, and with dimethylthiourea. It has the structural formula:

01 s- -'o (i,-NH

\0 0 -,-omc1 Br I (Alternative entering positions) Example 9 Chlormethylation of the thioindigo having the formula:

I CH3 CH3 Per Cent Per Cent 01 C1 Calcd. Found Anal:

For 1 GH;O1 group introduced 24. 2 26 03 For 2 'OH;O1 groups introduced 29. 0

A mixture of .monoand dichlormethylated products is obtained, chlormethylation taking place in the 6 positions.

We claim:

1. The halomethyl thioindigo compounds of the class consisting of those having the formulae:

n(GHaCl) and 3. The 5,5'-dichlormethyl 4,4 dichloro-6,6'- dimethyl thioindigo having the formula:

CICH CHaCl 01 s s i 4.. The dichlormethylated thloindigo having the formula:

5. The dichlormethyl-tetramethyl thioindigo of the formula:

l l O 2 011101) CH s s 3 9:11:01 H201 6. The monochlormethylated thioindlgo having the formula:

ClCHz- CH3 OH:

CARL M. SMITH. DAVID I. RANDALL.

No references cited. 

1. THE HALOMETHYL THIOINDIGO COMPOUNDS OF THE CLASS CONSISTTING OF THOSE HAVING THE FORMULAE: 